Electrophysiological Transcortical Diaschisis After Cortical Photothrombosis in Rat Brain

Buchkremer-Ratzmann, Irmgard; August, Matthias; Hagemann, Georg; Witte, Otto W.

doi:10.1161/01.str.27.6.1105

Cited by 211 publications

(113 citation statements)

References 42 publications

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“…Previous studies have revealed the presence of damage in contralateral brain areas after TBI. 32,33 The direct injury on the ipsilateral hemisphere may stress remote areas through transcallosal or transhemispheric diaschisis, 34 resulting in alterations in electrical activity, cerebral blood flow, and metabolites in the contralateral hemisphere. Inflammatory processes are also known to contribute to the contralateral responses after TBI.…”

Section: Discussionmentioning

confidence: 99%

Microglia/Macrophage Polarization Dynamics in White Matter after Traumatic Brain Injury

Wang

Zhang

et al. 2013

J Cereb Blood Flow Metab

411

331

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Mononuclear phagocytes are a population of multi-phenotypic cells and have dual roles in brain destruction/reconstruction. The phenotype-specific roles of microglia/macrophages in traumatic brain injury (TBI) are, however, poorly characterized. In the present study, TBI was induced in mice by a controlled cortical impact (CCI) and animals were killed at 1 to 14 days post injury. Real-time polymerase chain reaction (RT-PCR) and immunofluorescence staining for M1 and M2 markers were performed to characterize phenotypic changes of microglia/macrophages in both gray and white matter. We found that the number of M1-like phagocytes increased in cortex, striatum and corpus callosum (CC) during the first week and remained elevated until at least 14 days after TBI. In contrast, M2-like microglia/macrophages peaked at 5 days, but decreased rapidly thereafter. Notably, the severity of white matter injury (WMI), manifested by immunohistochemical staining for neurofilament SMI-32, was strongly correlated with the number of M1-like phagocytes. In vitro experiments using a conditioned medium transfer system confirmed that M1 microglia-conditioned media exacerbated oxygen glucose deprivation-induced oligodendrocyte death. Our results indicate that microglia/macrophages respond dynamically to TBI, experiencing a transient M2 phenotype followed by a shift to the M1 phenotype. The M1 phenotypic shift may propel WMI progression and represents a rational target for TBI treatment.

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Section: Discussionmentioning

confidence: 99%

Microglia/Macrophage Polarization Dynamics in White Matter after Traumatic Brain Injury

Wang

Zhang

et al. 2013

J Cereb Blood Flow Metab

411

331

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“…Regarding mechanism, long-lasting neuronal hyperexcitability in peri-infarct cortex is observed after stroke (Domann et al, 1993;Buchkremer-Ratzmann et al, 1996;Schiene et al, 1996;Mittmann et al, 1998;Neumann-Haefelin et al, 1998Redecker et al, 2002), peaking 4 weeks after stroke and persisting for 60 d (Mittmann et al, 1998). Zepeda et al (2004) demonstrated that regional reorganization 5 weeks after photothrombosis correlates with an increase in NMDA-receptor subunit levels from 1-5 weeks after stroke, while GABA levels remain reduced.…”

Section: Models For Functional Rewiringmentioning

confidence: 99%

In Vivo Calcium Imaging Reveals Functional Rewiring of Single Somatosensory Neurons after Stroke

Winship¹,

Murphy²

2008

Journal of Neuroscience

162

182

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Functional mapping and microstimulation studies suggest that recovery after stroke damage can be attributed to surviving brain regions taking on the functional roles of lost tissues. Although this model is well supported by data, it is not clear how activity in single neurons is altered in relation to cortical functional maps. It is conceivable that individual surviving neurons could adopt new roles at the expense of their usual function. Alternatively, neurons that contribute to recovery may take on multiple functions and exhibit a wider repertoire of neuronal processing. In vivo two-photon calcium imaging was used in adult mice within reorganized forelimb and hindlimb somatosensory functional maps to determine how the response properties of individual neurons and glia were altered during recovery from ischemic damage over a period of 2-8 weeks. Single-cell calcium imaging revealed that the limb selectivity of individual neurons was altered during recovery from ischemia, such that neurons normally selective for a single contralateral limb processed information from multiple limbs. Altered limb selectivity was most prominent in border regions between stroke-altered forelimb and hindlimb macroscopic map representations, and peaked 1 month after the targeted insult. Two months after stroke, individual neurons near the center of reorganized functional areas became more selective for a preferred limb. These previously unreported forms of plasticity indicate that in adult animals, seemingly hardwired cortical neurons first adopt wider functional roles as they develop strategies to compensate for loss of specific sensory modalities after forms of brain damage such as stroke.

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“…Modifications of the electrical activity (Buchkremer-Ratzmann et al, 1996;Meyer et al, 1970;Witte and Stoll, 1997), cerebral blood flow (Andrews, 1991;Dobkin et al, 1989), and/or metabolism (Andrews, 1991;Kuhl et al, 1980) have been reported at the cortical level (diaschisis), mainly within areas mirror to the lesion. In animal models of cerebral ischemia, Izumi et al (2002) recently reported a progressive edema in both hemispheres within the first few hours after MCA occlusion in rats.…”

Section: Introductionmentioning

confidence: 99%

Longitudinal Diffusion Changes in Cerebral Hemispheres after MCA Infarcts

Buffon

Molko

Hervé

et al. 2005

J Cereb Blood Flow Metab

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Diffusion tensor imaging can be used in vivo to assess the longitudinal and regional microstructural changes occurring after middle cerebral artery (MCA) infarcts in humans. Nine patients were investigated 1 week (D7), 1 (M1), 3 (M3), and 6 months (M6) after the occurrence of an isolated MCA infarction. First, an overall analysis was performed using histograms of mean diffusivity (MD) and fractional anisotropy (FA) in each hemisphere. Thereafter, the regional pattern of diffusion changes was investigated voxel by voxel with statistical parametric mapping 99. In the hemisphere ipsilateral to the infarction, histogram analysis revealed a significant decrease in FA between D7 and M6 associated with a progressive increase in MD from D7 to M3. Remote from the MCA territory, the voxel by voxel analyses detected a significant increase in MD within the thalamus at M3 and M6 and a reduction in FA along the pyramidal tract at M6. In the contralateral hemisphere, between D7 and M6, a significant hemispheric atrophy was observed in association with a global reduction in anisotropy, in the absence of distinctive regional diffusion changes. These results suggest that micro-and macrostructural tissue modifications can be detected with diffusion tensor imaging in regions remote from the ischemic area in both hemispheres.

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Electrophysiological Transcortical Diaschisis After Cortical Photothrombosis in Rat Brain

Abstract: Our results suggest that a neocortical infarction leads to hyperexcitability not only in its direct vicinity but also in the contralateral hemisphere. Such hyperexcitability may contribute to increased activation of contralateral brain areas and to functional reorganization after stroke.

Cited by 211 publications

References 42 publications

Microglia/Macrophage Polarization Dynamics in White Matter after Traumatic Brain Injury

Microglia/Macrophage Polarization Dynamics in White Matter after Traumatic Brain Injury

In Vivo Calcium Imaging Reveals Functional Rewiring of Single Somatosensory Neurons after Stroke

Longitudinal Diffusion Changes in Cerebral Hemispheres after MCA Infarcts

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